ABSTRACT: Support is requested for a study to examine continuities and discontinuities in psychiatric disorder between childhood and adolescence. Participants in the study will be 434 adolescents aged 13-18, who were first given detailed psychiatric assessments in 1983-85, when aged 7-11. One group consisted of children attending the child assessment clinics of the University of Pittsburgh's Department of Psychiatry (WPIC group, N=134). The second group consisted of children visiting their primary care pediatrician at a large Health Maintenance Organization for a wide range of reasons, including well-child care (HMO group, N=300). The WPIC group was sequential sample; the HMO group was the result of a two-stage design which over sampled for children with high scores on the Child Behavior Checklist (CBCL). Diagnostic procedures in both groups were the same: parent and child were interviewed separately using the NIMH Diagnostic Interview Schedule for Children (DISC), which permits most DSM-III diagnoses to be made. Additional information about family circumstances, and medical and educational history, were collected. Based on the DISC 89 (66%) of the WPIC group and 87 (29%) of the HMO group received one or more DSM-III diagnoses. Of the HMO group, only 6 (2%) had been referred for psychiatric treatment in the past year. We propose to reinterview all the children and parents using a revised DISC that also generates DSM-III diagnoses, and a new Social Adjustment Inventory for Children and Adolescents (SAICA). Treatment history, pubertal status, major environmental stressors, and nonpsychiatric outcomes (arrests, accidents, unplanned pregnancies) will be recorder from interview, self-report, and medical and judicial records. Despite evidence of high rates of unrecognized psychopathology in children never seen by a mental health professional, there is a scarcity of follow up studies of such children. We propose in this study to examine the consequences, for mental health and social functioning in adolescence, of recognized and unrecognized childhood disorders, and the implications for intervention. The specific aims are: (1) To examine which disorders increase in prevalence and which decrease; (2) To test hypotheses abut continuities and discontinuities within and between both specific disorders (e.g. Major Depressive Disorder) and broad diagnostic domains (e.g. internalizing disorders). We predict, for example, that externalizing disorders will show greater continuity than internalizing disorders. (3) To examine factors that may mediate continuities and discontinuities in psychopathology, such as exposure to treatment, environmental stressors, and the child's level of social functioning, or moderate them, such as puberty. Specifically, we shall (a) compare a subgroup of 176 disturbed children, 87 of whom received treatment for their childhood disorder while 89 did not, to explore the long term effects of treatment, controlling for other factors; (b) test the hypothesis that childhood disorder increases the risk of some environmental stressors (e.g. family dysfunction ) which in turn increases the risk of later disorder; (c) examine the effect of puberty in boys and girls controlling for age. (4) To determine the relationship between childhood and adolescent psychopathology and nonpsychiatric events such as arrest, accidents, and early unplanned pregnancies.